This invention relates to voltage regulators and particularly to high speed a.c. voltage regulators in which the output, regulated voltage responds almost instantly to changes in the input, unregulated voltage.
One problem of certain prior art voltage regulators is that they are relatively slow in response to changes in the unregulated input voltage. The present invention provides a rapid acting a.c. voltage regulator by selecting the proper primary windings of a voltage regulator transformer having a plurality of primary windings once during each voltage cycle to maintain a regulated voltage output. The primary windings are selected by obtaining a binary number which is related, in the embodiment to be described, to the positive peak of the unregulated voltage. The binary number obtained is used during the subsequent negative zero crossing to select the proper primary windings of the voltage regulator transformer to maintain a constant output voltage. It is thus an object of this invention to provide a high speed a.c. voltage regulator.